Rhythm perception, production, and synchronization during the perinatal period

Linking vestibular, tactile, and somatosensory rhythm perception to language development in infancy

First experiences with rhythm occur in the womb, with different rhythmic sources being available to the human fetus. Among sensory modalities, vestibular, tactile, and somatosensory perception plays a crucial role in early processing. However, a limited number of studies so far have specifically focused on VTS rhythms in language development. The present work investigated VTS rhythmic abilities and their role in language acquisition through two experiments with 45 infants (21 females, sex assigned at birth; M age = 661.6 days, SD = 192.6) with middle/high socioeconomic status. Specifically, 37 infants from the original sample completed Experiment 1, assessing VTS rhythmic abilities through a vibrotactile tool for music perception. In Experiment 2, linguistic abilities were evaluated in 40 participants from the same cohort, specifically testing phonological and prosodic processing. Discrimination abilities for rhythmic and linguistic stimuli were inferred from changes in pupil diameter to contingent visual stimuli over time, through a Tobii X-60 eye-tracker. The predictive effect of VTS rhythmic abilities on linguistic processing and the developmental changes occurring across ages were explored in the 32 infants who completed both Experiments 1 and 2 by means of generalized, additive and linear, mixed-effect models. Results are discussed in terms of cross-sensory (i.e., haptic to hearing) and cross-domain (i.e., music to language) effects of rhythm on language acquisition, with implications for typical and atypical development.

Which factors modulate spontaneous motor tempo? A systematic review of the literature

Intentionally or not, humans produce rhythmic behaviors (e.g., walking, speaking, and clapping). In 1974, Paul Fraisse defined rhythmic behavior as a periodic movement that obeys a temporal program specific to the subject and that depends less on the conditions of the action (p. 47). Among spontaneous rhythms, the spontaneous motor tempo (SMT) corresponds to the tempo at which someone produces movements in the absence of external stimuli, at the most regular, natural, and pleasant rhythm for him/her. However, intra- and inter-individual differences exist in the SMT values. Even if several factors have been suggested to influence the SMT (e.g., the age of participants), we do not yet know which factors actually modulate the value of the SMT. In this context, the objectives of the present systematic review are (1) to characterize the range of SMT values found in the literature in healthy human adults and (2) to identify all the factors modulating the SMT values in humans. Our results highlight that (1) the reference value of SMT is far from being a common value of 600 ms in healthy human adults, but a range of SMT values exists, and (2) many factors modulate the SMT values. We discuss our results in terms of intrinsic factors (in relation to personal characteristics) and extrinsic factors (in relation to environmental characteristics). Recommendations are proposed to assess the SMT in future research and in rehabilitative, educative, and sport interventions involving rhythmic behaviors.

Early social communication through music: State of the art and future perspectives

A growing body of research shows that the universal capacity for music perception and production emerges early in development. Possibly building on this predisposition, caregivers around the world often communicate with infants using songs or speech entailing song-like characteristics. This suggests that music might be one of the earliest developing and most accessible forms of interpersonal communication, providing a platform for studying early communicative behavior. However, little research has examined music in truly communicative contexts. The current work aims to facilitate the development of experimental approaches that rely on dynamic and naturalistic social interactions. We first review two longstanding lines of research that examine musical interactions by focusing either on the caregiver or the infant. These include defining the acoustic and non-acoustic features that characterize infant-directed (ID) music, as well as behavioral and neurophysiological research examining infants' processing of musical timing and pitch. Next, we review recent studies looking at early musical interactions holistically. This research focuses on how caregivers and infants interact using music to achieve co-regulation, mutual engagement, and increase affiliation and prosocial behavior. We conclude by discussing methodological, technological, and analytical advances that might empower a comprehensive study of musical communication in early childhood.

Infants show enhanced neural responses to musical meter frequencies beyond low-level features

Music listening often entails spontaneous perception and body movement to a periodic pulse-like meter. There is increasing evidence that this cross-cultural ability relates to neural processes that selectively enhance metric periodicities, even when these periodicities are not prominent in the acoustic stimulus. However, whether these neural processes emerge early in development remains largely unknown. Here, we recorded the electroencephalogram (EEG) of 20 healthy 5- to 6-month-old infants, while they were exposed to two rhythms known to induce the perception of meter consistently across Western adults. One rhythm contained prominent acoustic periodicities corresponding to the meter, whereas the other rhythm did not. Infants showed significantly enhanced representations of meter periodicities in their EEG responses to both rhythms. This effect is unlikely to reflect the tracking of salient acoustic features in the stimulus, as it was observed irrespective of the prominence of meter periodicities in the audio signals. Moreover, as previously observed in adults, the neural enhancement of meter was greater when the rhythm was delivered by low-pitched sounds. Together, these findings indicate that the endogenous enhancement of metric periodicities beyond low-level acoustic features is a neural property that is already present soon after birth. These high-level neural processes could set the stage for internal representations of musical meter that are critical for human movement coordination during rhythmic musical behavior. RESEARCH HIGHLIGHTS: 5- to 6-month-old infants were presented with auditory rhythms that induce the perception of a periodic pulse-like meter in adults. Infants showed selective enhancement of EEG activity at meter-related frequencies irrespective of the prominence of these frequencies in the stimulus. Responses at meter-related frequencies were boosted when the rhythm was conveyed by bass sounds. High-level neural processes that transform rhythmic auditory stimuli into internal meter templates emerge early after birth.

Auditory-motor synchronization varies among individuals and is critically shaped by acoustic features

The ability to synchronize body movements with quasi-regular auditory stimuli represents a fundamental trait in humans at the core of speech and music. Despite the long trajectory of the study of such ability, little attention has been paid to how acoustic features of the stimuli and individual differences can modulate auditory-motor synchrony. Here, by exploring auditory-motor synchronization abilities across different effectors and types of stimuli, we revealed that this capability is more restricted than previously assumed. While the general population can synchronize to sequences composed of the repetitions of the same acoustic unit, the synchrony in a subgroup of participants is impaired when the unit's identity varies across the sequence. In addition, synchronization in this group can be temporarily restored by being primed by a facilitator stimulus. Auditory-motor integration is stable across effectors, supporting the hypothesis of a central clock mechanism subserving the different articulators but critically shaped by the acoustic features of the stimulus and individual abilities.

Explaining flexible continuous speech comprehension from individual motor rhythms

When speech is too fast, the tracking of the acoustic signal along the auditory pathway deteriorates, leading to suboptimal speech segmentation and decoding of speech information. Thus, speech comprehension is limited by the temporal constraints of the auditory system. Here we ask whether individual differences in auditory-motor coupling strength in part shape these temporal constraints. In two behavioural experiments, we characterize individual differences in the comprehension of naturalistic speech as function of the individual synchronization between the auditory and motor systems and the preferred frequencies of the systems. Obviously, speech comprehension declined at higher speech rates. Importantly, however, both higher auditory-motor synchronization and higher spontaneous speech motor production rates were predictive of better speech-comprehension performance. Furthermore, performance increased with higher working memory capacity (digit span) and higher linguistic, model-based sentence predictability-particularly so at higher speech rates and for individuals with high auditory-motor synchronization. The data provide evidence for a model of speech comprehension in which individual flexibility of not only the motor system but also auditory-motor synchronization may play a modulatory role.

First school year tapping predicts children's third-grade literacy skills

Rhythmic skills have been repeatedly found to relate to children's early literacy skills. Using rhythmic tasks to predict language and reading performance seems a promising direction as they can be easily administered early as a screening test to identify at-risk children. In the present study, we measured Hungarian children's (N = 37) general cognitive abilities (working memory, non-verbal reasoning and rapid automatized naming), language and literacy skills (vocabulary, word reading, phonological awareness and spelling) and finger tapping performance in a longitudinal design in the first and third grades. We applied metronome stimuli in three tempi (80, 120, 150 bpm) using a synchronization-continuation paradigm and also measured participants' spontaneous motor tempo. While children's synchronization asynchrony was lower in third than in the first grade, with the exception of the slow-tempo trials, tapping consistency and continuation tapping success showed no development in this period. First-year tapping consistency in the slow-tempo tasks was associated with third-year reading and spelling outcomes. Our results show that the relation between tapping performance and literacy skills persists throughout the third school year, making the sensorimotor synchronization task a potentially effective instrument for predicting literacy outcomes, and a useful tool for early screening of reading difficulties.

Effects of Musical Classes on Motor Creativity According to Age, Sex, and Weight Status in Young Students: A Music-Oriented versus Conventional Education Plan

Motor creativity can be influenced by the specificity of the school-class environments (music-based education plans) and individual characteristics. This study aimed to investigate the effects of music oriented and conventional education plans on rhythmic perceptive capacity, motor creativity, and skill- and health-related fitness components in young students according to age, sex, and weight status. One hundred sixty-three young Italian students from elementary (second and fourth grade) and middle school (sixth and eighth grade) were enrolled in the study according to their education plan (music oriented or conventional). All participants were tested for rhythmic perceptive capacity (Stambak's test), motor creativity (Divergent Movement Ability test), skill-related (Körperkoordinationstest Für Kinder), and health-related (Multistage Fitness test) components. Individuals were also considered according to age (elementary and middle school), sex, and weight status. Significant age × education plan and sex × education plan interactions (p < 0.01) were found in motor creativity (locomotor and stability skills) and motor competence (balance and jumping-like activities). No significant weight status × education plan interaction was found. The predominant role of music in the music-oriented education plan appeared to foster the ability to enhance motor creativity in elementary and middle school students compared to the conventional plan. Moreover, music-oriented experience also seems relevant for expressing and exhibiting motor competence (i.e., balance) in relation to sex.

[The mechanisms involved in rocking toddlers]

If the tactile modality is fundamental in the infant's experience, there is a particular situation in which it is mobilized: rocking. Carrying a baby in one's arms or trying to soothe him will spontaneously lead the adult to rock him, whatever his culture. The ways of carrying out this rhythmic movement are varied, but all are characterized by a synchronous combination of somesthesic and vestibular stimulations repeated at regular intervals. The specificities of the tactile, vestibular and temporal modalities involved in rocking highlight the way in which rocking provides an essential support to the sensory and social development of the infant.

Longitudinal changes in infants' rhythmic arm movements during rattle-shaking play with mothers

From early on, infants produce a variety of rhythmic behaviors—an ability that likely supports later social communication. However, it is unclear, how this rhythmic motor production changes with age. Here, we investigated the coupling between infants' arm movements across the first year of life in a social context of a rattle-shaking play with their mothers. Through longitudinal measurements at 4, 6, 9, and 12 months of age using wearable motion trackers placed on infants' arms, we show that infants (N = 40) are similarly motivated to attempt rattle-shaking across the first year of life. However, with age, they make more rattling movements with an increased frequency. Their left and right arm movements become more coupled during rattle-shaking, as shown by an increase in wavelet coherence. Infants produced more rattling movements when they were rattling alone than when their mothers were rattling or singing simultaneously. There were no differences between infants' individual and social rattling in between-arms coherence. Our results may help to understand rhythmic arm movements as precursors of motor social coordination.

Skin-to-skin SDF positioning: The key to intersubjective intimacy between mother and very preterm newborn-A pilot matched-pair case-control study

Background

Skin-to-skin contact (SSC) has been widely studied in NICU and several meta-analyses have looked at its benefits, for both the baby and the parent. However, very few studies have investigated SSC' benefits for communication, in particular in the very-preterm newborn immediately after birth.

Aims

To investigate the immediate benefits of Supported Diagonal Flexion (SDF) positioning during SSC on the quality of mother-very-preterm newborn communication and to examine the coordination of the timing of communicative behaviors, just a few days after birth.

Subjects and study design

Monocentric prospective matched-pair case-control study. Thirty-four mothers and their very preterm infants (27 to 31 + 6 weeks GA, mean age at birth: 30 weeks GA) were assigned to one of the two SSC positioning, either the Vertical Control positioning (n = 17) or the SDF Intervention positioning (n = 17). Mother and newborn were filmed during the first 5 min of their first SSC.

Outcome measures

Infants' states of consciousness according to the Assessment of Preterm Infants' Behavior scale (APIB). Onset and duration of newborns' and mothers' vocalizations and their temporal proximity within a 1-s time-window.

Results

In comparison with the Vertical group, very preterm newborns in the SDF Intervention Group spent less time in a drowsy state and more in deep sleep. At 3.5 days of life, newborns' vocal production in SSC did not differ significantly between the two groups. Mothers offered a denser vocal envelope in the SDF group than in the Vertical group and their vocalizations were on average significantly longer. Moreover, in a one-second time-frame, temporal proximity of mother-very preterm newborn behaviors was greater in the SDF Intervention Group.

Conclusion

Although conducted on a limited number of dyads, our study shows that SDF positioning fosters mother-very preterm newborn intimate encounter during the very first skin to skin contact after delivery. Our pioneer data sheds light on the way a mother and her very preterm vocally meet, and constitutes a pilot step in the exploration of innate intersubjectivity in the context of very preterm birth.

Musical abilities in children with developmental cerebellar anomalies

Developmental Cerebellar Anomalies (DCA) are rare diseases (e.g., Joubert syndrome) that affect various motor and non-motor functions during childhood. The present study examined whether music perception and production are affected in children with DCA. Sixteen children with DCA and 37 healthy matched control children were tested with the Montreal Battery for Evaluation of Musical Abilities (MBEMA) to assess musical perception. Musical production was assessed using two singing tasks: a pitch-matching task and a melodic reproduction task. Mixed model analyses showed that children with DCA were impaired on the MBEMA rhythm perception subtest, whereas there was no difference between the two groups on the melodic perception subtest. Children with DCA were also impaired in the melodic reproduction task. In both groups, singing performance was positively correlated with rhythmic and melodic perception scores, and a strong correlation was found between singing ability and oro-bucco-facial praxis in children with DCA. Overall, children with DCA showed impairments in both music perception and production, although heterogeneity in cerebellar patient’s profiles was highlighted by individual analyses. These results confirm the role of the cerebellum in rhythm processing as well as in the vocal sensorimotor loop in a developmental perspective. Rhythmic deficits in cerebellar patients are discussed in light of recent work on predictive timing networks including the cerebellum. Our results open innovative remediation perspectives aiming at improving perceptual and/or production musical abilities while considering the heterogeneity of patients’ clinical profiles to design music-based therapies.

The Groove Enhancement Machine (GEM): A Multi-Person Adaptive Metronome to Manipulate Sensorimotor Synchronization and Subjective Enjoyment

Synchronization of movement enhances cooperation and trust between people. However, the degree to which individuals can synchronize with each other depends on their ability to perceive the timing of others’ actions and produce movements accordingly. Here, we introduce an assistive device—a multi-person adaptive metronome—to facilitate synchronization abilities. The adaptive metronome is implemented on Arduino Uno circuit boards, allowing for negligible temporal latency between tapper input and adaptive sonic output. Across five experiments—two single-tapper, and three group (four tapper) experiments, we analyzed the effects of metronome adaptivity (percent correction based on the immediately preceding tap-metronome asynchrony) and auditory feedback on tapping performance and subjective ratings. In all experiments, tapper synchronization with the metronome was significantly enhanced with 25–50% adaptivity, compared to no adaptation. In group experiments with auditory feedback, synchrony remained enhanced even at 70–100% adaptivity; without feedback, synchrony at these high adaptivity levels returned to near baseline. Subjective ratings of being in the groove, in synchrony with the metronome, in synchrony with others, liking the task, and difficulty all reduced to one latent factor, which we termed enjoyment. This same factor structure replicated across all experiments. In predicting enjoyment, we found an interaction between auditory feedback and metronome adaptivity, with increased enjoyment at optimal levels of adaptivity only with auditory feedback and a severe decrease in enjoyment at higher levels of adaptivity, especially without feedback. Exploratory analyses relating person-level variables to tapping performance showed that musical sophistication and trait sadness contributed to the degree to which an individual differed in tapping stability from the group. Nonetheless, individuals and groups benefitted from adaptivity, regardless of their musical sophistication. Further, individuals who tapped less variably than the group (which only occurred ∼25% of the time) were more likely to feel “in the groove.” Overall, this work replicates previous single person adaptive metronome studies and extends them to group contexts, thereby contributing to our understanding of the temporal, auditory, psychological, and personal factors underlying interpersonal synchrony and subjective enjoyment during sensorimotor interaction. Further, it provides an open-source tool for studying such factors in a controlled way.

Anticipatory regulation of cardiovascular system on the emergence of auditory-motor interaction in young infants

Humans develop auditory-motor interaction to produce a variety of rhythmic sounds using body movements, which are often produced and amplified with tools, such as drumming. The extended production of sounds allows us to express a wide range of emotions, accompanied by physiological changes. According to previous studies, even young infants enhance movements in response to auditory feedback. However, their exhibition of physiological adaptation on the emergence of auditory-motor interaction is unclear. We investigated the movement and cardiac changes associated with auditory feedback to spontaneous limb movements in 3-month-old infants. The results showed that infants increased the frequency of limb movements inducing auditory feedback, while they exhibited a more regular rhythm of the limb movements. Furthermore, heart rate increase associated with the limb movement was first inhibited immediately after the timing of the auditory feedback, which may reflect sustained attention to the auditory stimuli. Then, through auditory-motor experience, the heart rate increase was inhibited even prior to the auditory feedback, leading to suppression of the peak intensity of the heart rate increase. These findings suggest that young infants regulate the cardiovascular system as well as limb movements in anticipation of the auditory feedback. The anticipatory regulation associated with movement and attentional changes may contribute to reduced cardiovascular stress in auditory-motor interaction, and provide a developmental basis for more sophisticated goal-directed behavior of producing rhythmic sounds.

In sync with your child: The potential of parent-child electroencephalography in developmental research

Healthy interaction between parent and child is foundational for the child's socioemotional development. Recently, an innovative paradigm shift in electroencephalography (EEG) research has enabled the simultaneous measurement of neural activity in caregiver and child. This dual-EEG or hyperscanning approach, termed parent-child dual-EEG, combines the strength of both behavioral observations and EEG methods. In this review, we aim to inform on the potential of dual-EEG in parents and children (0-6 years) for developmental researchers. We first provide a general overview of the dual-EEG technique and continue by reviewing the first empirical work on the emerging field of parent-child dual-EEG, discussing the limited but fascinating findings on parent-child brain-to-behavior and brain-to-brain synchrony. We then continue by providing an overview of dual-EEG analysis techniques, including the technical challenges and solutions one may encounter. We finish by discussing the potential of parent-child dual-EEG for the future of developmental research. The analysis of multiple EEG data is technical and challenging, but when performed well, parent-child EEG may transform the way we understand how caregiver and child connect on a neurobiological level. Importantly, studying objective physiological measures of parent-child interactions could lead to the identification of novel brain-to-brain synchrony markers of interaction quality.

Memory-Paced Tapping to Auditory Rhythms: Effects of Rate, Speech, and Motor Engagement

PURPOSE

Humans have a near-automatic tendency to entrain their motor actions to rhythms in the environment. Entrainment has been hypothesized to play an important role in processing naturalistic stimuli, such as speech and music, which have intrinsically rhythmic properties. Here, we studied two facets of entraining one's rhythmic motor actions to an external stimulus: (a) synchronized finger tapping to auditory rhythmic stimuli and (b) memory-paced reproduction of a previously heard rhythm.

METHOD

Using modifications of the Synchronization-Continuation tapping paradigm, we studied how these two rhythmic behaviors were affected by different stimulus and task features. We tested synchronization and memory-paced tapping for a broad range of rates, from stimulus onset asynchrony of subsecond to suprasecond, both for strictly isochronous tone sequences and for rhythmic speech stimuli (counting from 1 to 10), which are more ecological yet less isochronous. We also asked what role motor engagement plays in forming a stable internal representation for rhythms and guiding memory-paced tapping.

RESULTS AND CONCLUSIONS

Our results show that individuals can flexibly synchronize their motor actions to a very broad range of rhythms. However, this flexibility does not extend to memory-paced tapping, which is accurate only in a narrower range of rates, around ~1.5 Hz. This pattern suggests that intrinsic rhythmic defaults in the auditory and/or motor system influence the internal representation of rhythms, in the absence of an external pacemaker. Interestingly, memory-paced tapping for speech rhythms and simple tone sequences shared similar "optimal rates," although with reduced accuracy, suggesting that internal constraints on rhythmic entrainment generalize to more ecological stimuli. Last, we found that actively synchronizing to tones versus passively listening to them led to more accurate memory-paced tapping performance, which emphasizes the importance of action-perception interactions in forming stable entrainment to external rhythms.

Collective Rhythm as an Emergent Property During Human Social Coordination

The literature on social interactions has shown that participants coordinate not only at the behavioral but also at the physiological and neural levels, and that this coordination gives a temporal structure to the individual and social dynamics. However, it has not been fully explored whether such temporal patterns emerge during interpersonal coordination beyond dyads, whether this phenomenon arises from complex cognitive mechanisms or from relatively simple rules of behavior, or which are the sociocultural processes that underlie this phenomenon. We review the evidence for the existence of group-level rhythmic patterns that result from social interactions and argue that the complexity of group dynamics can lead to temporal regularities that cannot be predicted from the individual periodicities: an emergent collective rhythm. Moreover, we use this interpretation of the literature to discuss how taking into account the sociocultural niche in which individuals develop can help explain the seemingly divergent results that have been reported on the social influences and consequences of interpersonal coordination. We make recommendations on further research to test these arguments and their relationship to the feeling of belonging and assimilation experienced during group dynamics.

A Dynamical, Radically Embodied, and Ecological Theory of Rhythm Development

Musical rhythm abilities-the perception of and coordinated action to the rhythmic structure of music-undergo remarkable change over human development. In the current paper, we introduce a theoretical framework for modeling the development of musical rhythm. The framework, based on Neural Resonance Theory (NRT), explains rhythm development in terms of resonance and attunement, which are formalized using a general theory that includes non-linear resonance and Hebbian plasticity. First, we review the developmental literature on musical rhythm, highlighting several developmental processes related to rhythm perception and action. Next, we offer an exposition of Neural Resonance Theory and argue that elements of the theory are consistent with dynamical, radically embodied (i.e., non-representational) and ecological approaches to cognition and development. We then discuss how dynamical models, implemented as self-organizing networks of neural oscillations with Hebbian plasticity, predict key features of music development. We conclude by illustrating how the notions of dynamical embodiment, resonance, and attunement provide a conceptual language for characterizing musical rhythm development, and, when formalized in physiologically informed dynamical models, provide a theoretical framework for generating testable empirical predictions about musical rhythm development, such as the kinds of native and non-native rhythmic structures infants and children can learn, steady-state evoked potentials to native and non-native musical rhythms, and the effects of short-term (e.g., infant bouncing, infant music classes), long-term (e.g., perceptual narrowing to musical rhythm), and very-long term (e.g., music enculturation, musical training) learning on music perception-action.

Genome-wide association study of musical beat synchronization demonstrates high polygenicity

Moving in synchrony to the beat is a fundamental component of musicality. Here we conducted a genome-wide association study to identify common genetic variants associated with beat synchronization in 606,825 individuals. Beat synchronization exhibited a highly polygenic architecture, with 69 loci reaching genome-wide significance (P < 5 × 10^-8) and single-nucleotide-polymorphism-based heritability (on the liability scale) of 13%-16%. Heritability was enriched for genes expressed in brain tissues and for fetal and adult brain-specific gene regulatory elements, underscoring the role of central-nervous-system-expressed genes linked to the genetic basis of the trait. We performed validations of the self-report phenotype (through separate experiments) and of the genome-wide association study (polygenic scores for beat synchronization were associated with patients algorithmically classified as musicians in medical records of a separate biobank). Genetic correlations with breathing function, motor function, processing speed and chronotype suggest shared genetic architecture with beat synchronization and provide avenues for new phenotypic and genetic explorations.

Tapping to Music Predicts Literacy Skills of First-Grade Children

The ability to synchronise one's movements to the sound of a regular beat has been found to be associated with children's language and reading abilities. Sensorimotor synchronisation or tapping performance can among other factors [e.g., working memory and rapid automatized naming (RAN)] predict phonological awareness and word reading accuracy and fluency of first graders. While tapping tasks that use a simple metronome sound are more often used, applying musical stimuli has the potential advantage of being more engaging and motivating for children. In the present study, we investigated whether tapping to a metronome beat or complex musical stimuli would predict phonological awareness and reading outcomes of Hungarian 6-7-year olds (N=37). We also measured participants' general cognitive abilities (RAN, non-verbal intelligence and verbal working memory). Our results show that phonological awareness, spelling and reading accuracy were associated with the musical tasks while reading fluency was predicted by the metronome trials. Our findings suggest that complex musical tasks should be considered when investigating this age group, as they were, in general, more effective in predicting literacy outcomes.

Rate of infant carrying impacts infant spontaneous motor tempo

Rhythm production is a critical component of human interaction, not least forming the basis of our musicality. Infants demonstrate a spontaneous motor tempo (SMT), or natural rate of rhythmic movement. Here, we ask whether infant SMT is influenced by the rate of locomotion infants experience when being carried. Ten-month-old, non-walking infants were tested using a free drumming procedure before and after 10 min of being carried by an experimenter walking at a slower (98 BPM) or faster (138 BPM) than average tempo. We find that infant SMT is differentially impacted by carrying experience dependent on the tempo at which they were carried: infants in the slow-walked group exhibited a slower SMT from pre-test to post-test, while infants in the fast-walked group showed a faster SMT from pre-test to post-test. Heart rate data suggest that this effect is not due to a general change in the state of arousal. We argue that being carried during caregiver locomotion is a predominant experience for infants throughout the first years of life, and as a source of regular, vestibular, information, may at least partially form the basis of their sense of rhythm.

The Importance of Rhythmic Stimulation for Preterm Infants in the NICU

The fetal environment provides the fetus with multiple potential sources of rhythmic stimulation that are not present in the NICU. Maternal breathing, heartbeats, walking, dancing, running, speaking, singing, etc., all bathe the fetus in an environment of varied rhythmic stimuli: vestibular, somatosensory, tactile, and auditory. In contrast, the NICU environment does not offer the same proportion of rhythmic stimulation. After analyzing the lack of rhythmic stimulation in the NICU, this review highlights the different proposals for vestibular and/or auditory rhythmic stimulation offered to preterm infants alone and with their parents. The focus is on the beneficial effects of auditory and vestibular stimulation involving both partners of the mother-infant dyad. A preliminary study on the influence of a skin-to-skin lullaby on the stability of maternal behavior and on the tonic emotional manifestations of the preterm infant is presented as an example. The review concludes with the importance of introducing rhythmic stimulations in the NICU.

Cortical Processing of Multimodal Sensory Learning in Human Neonates

Following birth, infants must immediately process and rapidly adapt to the array of unknown sensory experiences associated with their new ex-utero environment. However, although it is known that unimodal stimuli induce activity in the corresponding primary sensory cortices of the newborn brain, it is unclear how multimodal stimuli are processed and integrated across modalities. The latter is essential for learning and understanding environmental contingencies through encoding relationships between sensory experiences; and ultimately likely subserves development of life-long skills such as speech and language. Here, for the first time, we map the intracerebral processing which underlies auditory-sensorimotor classical conditioning in a group of 13 neonates (median gestational age at birth: 38 weeks + 4 days, range: 32 weeks + 2 days to 41 weeks + 6 days; median postmenstrual age at scan: 40 weeks + 5 days, range: 38 weeks + 3 days to 42 weeks + 1 days) with blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (MRI) and magnetic resonance (MR) compatible robotics. We demonstrate that classical conditioning can induce crossmodal changes within putative unimodal sensory cortex even in the absence of its archetypal substrate. Our results also suggest that multimodal learning is associated with network wide activity within the conditioned neural system. These findings suggest that in early life, external multimodal sensory stimulation and integration shapes activity in the developing cortex and may influence its associated functional network architecture.

Developmental trajectory of interpersonal motor alignment: Positive social effects and link to social cognition

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Interpersonal motor alignment (IMA) has positive effects on healthy social life.

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IMA - mimicry, synchrony, automatic imitation - is studied throughout development.

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It relies on motor resonance brain mechanisms identified throughout development.

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It is modulated by contextual and personal factors.

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IMA is underinvestigated in adolescence, yet it may aid to enhance resilience.

Interpersonal motor alignment is a ubiquitous behavior in daily social life. It is a building block for higher social cognition, including empathy and mentalizing and promotes positive social effects. It can be observed as mimicry, synchrony and automatic imitation, to name a few. These phenomena rely on motor resonance processes, i.e., a direct link between the perception of an action and its execution. While a considerable literature debates its underlying mechanisms and measurement methods, the question of how motor alignment comes about and changes in ontogeny all the way until adulthood, is rarely discussed specifically. In this review we will focus on the link between interpersonal motor alignment, positive social effects and social cognition in infants, children, and adolescents, demonstrating that this link is present early on in development. Yet, in reviewing the existing literature pertaining to social psychology and developmental social cognitive neuroscience, we identify a knowledge gap regarding the healthy developmental changes in interpersonal motor alignment especially in adolescence.

Spontaneous and stimulus-driven rhythmic behaviors in ADHD adults and controls

Many aspects of human behavior are inherently rhythmic, requiring production of rhythmic motor actions as well as synchronizing to rhythms in the environment. It is well-established that individuals with ADHD exhibit deficits in temporal estimation and timing functions, which may impact their ability to accurately produce and interact with rhythmic stimuli. In the current study we seek to understand the specific aspects of rhythmic behavior that are implicated in ADHD. We specifically ask whether they are attributed to imprecision in the internal generation of rhythms or to reduced acuity in rhythm perception. We also test key predictions of the Preferred Period Hypothesis, which suggests that both perceptual and motor rhythmic behaviors are biased towards a specific personal 'default' tempo. To this end, we tested several aspects of rhythmic behavior and the correspondence between them, including spontaneous motor tempo (SMT), preferred auditory perceptual tempo (PPT) and synchronization-continuations tapping in a broad range of rhythms, from sub-second to supra-second intervals. Moreover, we evaluate the intra-subject consistency of rhythmic preferences, as a means for testing the reality and reliability of personal 'default-rhythms'. We used a modified operational definition for assessing SMT and PPT, instructing participants to tap or calibrate the rhythms most comfortable for them to count along with, to avoid subjective interpretations of the task. Our results shed new light on the specific aspect of rhythmic deficits implicated in ADHD adults. We find that individuals with ADHD are primarily challenged in producing and maintaining isochronous self-generated motor rhythms, during both spontaneous and memory-paced tapping. However, they nonetheless exhibit good flexibility for synchronizing to a broad range of external rhythms, suggesting that auditory-motor entrainment for simple rhythms is preserved in ADHD, and that the presence of an external pacer allows overcoming their inherent difficulty in self-generating isochronous motor rhythms. In addition, both groups showed optimal memory-paced tapping for rhythms near their 'counting-based' SMT and PPT, which were slightly faster in the ADHD group. This is in line with the predictions of the Preferred Period Hypothesis, indicating that at least for this well-defined rhythmic behavior (i.e., counting), individuals tend to prefer similar time-scales in both motor production and perceptual evaluation.

Temporal rate is not a distinct perceptual metric

Sensory adaptation experiments have revealed the existence of 'rate after-effects' - adapting to a relatively fast rate makes an intermediate test rate feel slow, and adapting to a slow rate makes the same moderate test rate feel fast. The present work aims to deconstruct the concept of rate and clarify how exactly the brain processes a regular sequence of sensory signals. We ask whether rate forms a distinct perceptual metric, or whether it is simply the perceptual aggregate of the intervals between its component signals. Subjects were exposed to auditory or visual temporal rates (a 'slow' rate of 1.5 Hz and a 'fast' rate of 6 Hz), before being tested with single unfilled intervals of varying durations. Results show adapting to a given rate strongly influences the perceived duration of a single empty interval. This effect is robust across both interval reproduction and duration discrimination judgments. These findings challenge our understanding of rate perception. Specifically, they suggest that contrary to some previous assertions, the perception of sequence rate is strongly influenced by the perception of the sequence's component duration intervals.

Infant Movement Response to Auditory Rhythm

Rhythmic entrainment occurs when an auditory rhythm drives an internal movement oscillator, thus providing a continuous time reference that improves temporal and spatial movement parameters. Entrainment processes and outcomes are well known for adults, but research is lacking for infants who might benefit from diagnosis and treatment of irregular rhythms within biological, sensorimotor, cognitive, and social domains. The present study used a combination of inertial measurement units and custom-made software to determine the amount, tempo, and regularity of movement in 28 infants aged 6-10 months while they were exposed to silence, an irregular rhythmic cue, or a regular rhythmic cue with tempo changes. We also assessed changes in the infants' movement parameters following a one-week rhythm training protocol. While results revealed no significant effect of auditory condition on amount or tempo of movement, infant movement was significantly more regular when infants were exposed to 120 bpm (beats per minute) than to an irregular rhythmic cue or a 10% faster rhythmic cue (132 bpm). Infants showed no notable changes in movement amount, tempo, or regularity following one week of training involving auditory and physical rhythm. Overall, infants seem to engage in spontaneous movements with or without auditory rhythm but may not show tempo sensitivity through their movements. Increased movement regularity suggests that 120 bpm may be a preferred tempo for infants, at which they are more likely to demonstrate well-timed movements that may reflect interval entrainment. Infants' auditory-motor systems appear not to respond to a 1-week rhythm training protocol.

The body comes first. Embodied reparation and the co-creation of infant bodily-self

During infancy relational experiences of body-to-body exchanges (i.e., embodied interactions) contribute to the infant's bodily perception. Early embodied interactions are based on countless multimodal reciprocal exchanges, in which mother and infant contribute to interpersonal rhythmic cycles of co-regulation (i.e., attunement). However, it remains unclear how infants and their mothers actually accomplish attunement in their exchanges. Interactions between mothers and their infants typically fluctuate between attuned and misattuned states and recovery attunement states by a process called 'reparation'. Here, we discuss recent neuroscientific evidence that provides insight into the mechanisms underpinning the concepts of attunement and misattunement in early embodied interactions. We propose that a process of embodied reparation might be achieved within the dyad through tactile contact behaviors (e.g., skin-to-skin, affectionate touch) and maternal interoceptive sensitivity (i.e., ability to perceive internal input about the state of one's own body). We describe how these elements that mothers provide during embodied interactions with their infants, might contribute not only to bodily attunement, but also to co-create the infant bodily-self.

Neurobehavioral Interpersonal Synchrony in Early Development: The Role of Interactional Rhythms

Social interactions are essential for understanding others' actions and their mental and affective states. Specifically, interpersonal coordination - also referred to as synchrony - allows actors to adjust their behaviors to one another and thus demonstrate their connectedness to each other. Much behavioral research has demonstrated the primacy of mutually synchronized social exchanges in early development. Additionally, new methodological advances now allow us to examine interpersonal synchrony not only at the behavioral and physiological but also neural level. Nevertheless, it remains unclear how infants and their caregivers actually achieve interpersonal synchrony in their exchanges. Here we discuss recent evidence showing that adults provide rhythmical information during early social interactions with their infants, such as affective touch and singing. We propose that entrainment to these social rhythms underlies the formation of interpersonal synchrony and thus stimulates reciprocal interactions between infants and their caregivers.

Neuroprocessing Mechanisms of Music during Fetal and Neonatal Development: A Role in Neuroplasticity and Neurodevelopment

The primary aim of this viewpoint article is to examine recent literature on fetal and neonatal processing of music. In particular, we examine the behavioral, neurophysiological, and neuroimaging literature describing fetal and neonatal music perception and processing to the first days of term equivalent life. Secondly, in light of the recent systematic reviews published on this topic, we discuss the impact of music interventions on the potential neuroplasticity pathways through which the early exposure to music, live or recorded, may impact the fetal, preterm, and full-term infant brain. We conclude with recommendations for music stimuli selection and its role within the framework of early socioemotional development and environmental enrichment.

Sensorimotor Synchronization With Auditory and Visual Modalities: Behavioral and Neural Differences

It has long been known that the auditory system is better suited to guide temporally precise behaviors like sensorimotor synchronization (SMS) than the visual system. Although this phenomenon has been studied for many years, the underlying neural and computational mechanisms remain unclear. Growing consensus suggests the existence of multiple, interacting, context-dependent systems, and that reduced precision in visuo-motor timing might be due to the way experimental tasks have been conceived. Indeed, the appropriateness of the stimulus for a given task greatly influences timing performance. In this review, we examine timing differences for sensorimotor synchronization and error correction with auditory and visual sequences, to inspect the underlying neural mechanisms that contribute to modality differences in timing. The disparity between auditory and visual timing likely relates to differences in the processing specialization between auditory and visual modalities (temporal vs. spatial). We propose this difference could offer potential explanation for the differing temporal abilities between modalities. We also offer suggestions as to how these sensory systems interface with motor and timing systems.

The manual orienting response habituation to repeated tactile stimuli in preterm neonates: Discrimination of stimulus locations and interstimulus intervals

Preterm infants frequently develop atypical sensory profiles, the tactile modality being particularly affected. However, there is a lack of recent investigation of neonatal tactile perception in a passive context, especially in preterms who are particularly exposed to this tactile stimuli. Our aims were to provide evidence of orienting responses (behavioral modifications directing subject's attention towards stimuli) and habituation to passive tactile stimuli in preterm neonates, to explore their ability to perceive spatial and temporal aspects of the stimulus, and to evaluate the effect of clinical factors on these abilities. We included 61 preterm neonates, born between 32 and 34 weeks of gestational age. At 35 weeks of corrected gestational age, we measured orienting responses (forearm, hand, and fingers movements) during vibrotactile stimulation of their hand and forearm; during a habituation and dishabituation paradigm, the dishabituation being either a location change or a pause in the stimulation sequence. Preterm newborns displayed a manual orienting response to vibrotactile stimuli which significantly decreased when the stimulus was repeated, regardless of the stimulated location on the limb. Habituation was delayed in subjects born at a younger gestational age, smaller birth weight, and having experienced more painful care procedures. Preterm neonates perceived changes in stimulus location and interstimulus time interval. Our findings provide insights on several aspects of the perception of repeated tactile stimuli by preterm neonates, and the first evidence of the early development of temporal processing abilities in the tactile modality. Future work will investigate the links between this ability and neurodevelopmental disorders.

Synchrony and emotion in children and adults

This study examined both the development of synchronisation activities and the way emotion affects these activities in children and adults. Children aged from 3 to 8 years, as well as adults, performed a spontaneous motor tempo (SMT) task and a synchronisation task with a 500-millisecond and 700-millisecond inter-stimulus interval (ISI), followed by a continuation task, in both an emotion-free and an emotional context (High-Arousal, Low-Arousal, and Neutral). The results showed that the SMT was faster and more variable in the younger children. In addition, the younger children found it more difficult to slow down their tapping rate in synchrony with the 700-millisecond ISI, with the result that they quickly returned to their internal tempo in the continuation phase. In contrast, the 8-year-olds' synchronisation performance was close to that of the adults. However, despite developmental changes in synchronisation skills, all the participants produced faster tempi in both the SMT and the synchronisation task for the High-Arousal emotion than for the other emotions. This suggests that emotions induce an automatic distortion of motor timing as has also been observed for the perception of time.

Do fetuses move their lips to the sound that they hear? An observational feasibility study on auditory stimulation in the womb

Background

We investigate in this feasibility study whether specific lip movements increase prenatally when hearing a particular sound. We hypothesised that fetuses would produce more mouth movements resembling those required to make the sound stimulus they heard (i.e. mouth stretch) compared with a no-sound control group who heard no specific auditory stimuli. Secondly, we predicted that fetuses hearing the sound would produce a similar number of mouth movements unrelated to the sound heard (i.e. lip pucker) as the no-sound group of fetuses.

Methods

In an observational feasibility study, 17 fetuses were scanned twice at 32 and 36 weeks of gestation, and two different types of mouth movements were recorded. Three fetuses received an auditory stimulus, and 14 did not. A generalised mixed effects log-linear model was used to determine statistical significance.

Results

Fetuses in the sound group performed one specific mouth movement (mouth stretch) significantly more frequently than fetuses in the no-sound group. A significant interaction between group and gestational age indicates that there was differential change in this specific movement as age increases (X² = 7.58 on 1 df, p = 0.006), with the no-sound group showing a decline of 76 % between 32 weeks and 36 weeks (p < 0.001), whereas the sound group showed no significant change over time (p = 0.41). There was no significant difference between the sound group and no-sound group in the frequency of lip puckering—the second, unrelated mouth movement (p = 0.35).

Conclusions

These results suggest that a sound stimulus is associated with an increase in specific, rather than general, mouth movements. The results are informative for the development of infant speech and potentially could also lead to a diagnostic test for deafness in utero. More research is needed to replicate this research with a randomised design and with a range of different auditory stimuli which would be produced with different mouth movements, such as “o” which would be seen as pursed lips.

Electronic supplementary material

The online version of this article (doi:10.1186/s40814-016-0053-3) contains supplementary material, which is available to authorized users.

Children can implicitly, but not voluntarily, direct attention in time

Children are able to use spatial cues to orient their attention to discrete locations in space from around 4 years of age. In contrast, no research has yet investigated the ability of children to use informative cues to voluntarily predict when an event will occur in time. The spatial and temporal attention task was used to determine whether children were able to voluntarily orient their attention in time, as well as in space: symbolic spatial and temporal cues predicted where or when an imperative target would appear. Thirty typically developing children (average age 11 yrs) and 32 adults (average age 27 yrs) took part. Confirming previous findings, adults made use of both spatial and temporal cues to optimise behaviour, and were significantly slower to respond to invalidly cued targets in either space or time. Children were also significantly slowed by invalid spatial cues, demonstrating their use of spatial cues to guide expectations. In contrast, children’s responses were not slowed by invalid temporal cues, suggesting that they were not using the temporal cue to voluntarily orient attention through time. Children, as well as adults, did however demonstrate signs of more implicit forms of temporal expectation: RTs were faster for long versus short cue-target intervals (the variable foreperiod effect) and slower when the preceding trial’s cue-target interval was longer than that on the current trial (sequential effects). Overall, our results suggest that although children implicitly made use of the temporally predictive information carried by the length of the current and previous trial’s cue-target interval, they could not deliberately use symbolic temporal cues to speed responses. The developmental trajectory of the ability to voluntarily use symbolic temporal cues is therefore delayed, relative both to the use of symbolic (arrow) spatial cues, and to the use of implicit temporal information.